An animal model tumor system (rat mammary adenocarcinoma) will be used to develop a series of sensitive, quantitative assay techniques designed to evaluate the various parameters involving the interaction between a host's immune system and a growing neoplasm. The several branches of the cellular immune system will be separated by adsorption-elution techniques and their relationship with each other, with soluble tumor associated antigens and with the humoral immune system will be studied with respect to their effect on the growth and viability of target tumor cells in vitro as well as in vivo. The development of refined methods to quantitate target cell recognition and cytotoxic capacity of effector cells will aid in these studies and will lead to a means of precisely evaluating the extent of involvement of each segment of an individuals's immune system with respect to his neoplasm.